For years now, news of distributed denial of services (DDoS) attacks has been an all-too-familiar topic of print, online, and broadcast journalism. Sparked by more sophisticated technology and ever-more-brazen hackers, incidents of massive site failures, stolen data, and outright trickery are mounting up. DDoS attacks might have increased by 55 percent over 2020, but countervailing forces in the form of familiar technology are coming into play.
What is a CDN?
Each content delivery network (CDN) is a group of servers linked to a data center and located strategically around the world to reduce file loading times and latency. This close-to-home approach to web services helps CDNs fulfill their job: to provide content delivery that’s efficient, fast, and secure. For many organizations built on internet communications, CDNs are the engine of their operations.
How Do CDNs Mitigate DDoS Attacks?
Although commercial content delivery networks (CDNs) have been around since the 1980s, they are taking a new role in combatting malicious software in cyberattacks. Using CDNs for DDoS attacks is a new way to fight a varied group of exploits. DDoS attacks aim a tsunami of junk data at a target website. Sometimes attacks slow down normal website services. Other times, they stop site operations altogether.
The business impact of these disruptions can be grave. Average DDoS attack recovery costs for enterprise businesses average an eye-popping $1.85 million. Astonishing? Maybe, but consider the revenue lost to downtime, customer loyalty, possible compliance penalties and many, often lengthy recovery processes.
So, what can CDNs do to find, identify, and reduce the destructive power of DDoS attacks? Quite a bit, really. Here’s the lineup of CDN-related attack mitigation capabilities.
Identify DDoS threats. CDN server software uses threat intelligence measures to gather data from the behavior of millions of hosted websites. When combined with histories of vulnerable IP hosts and addresses, predictive data analytics helps security teams to set up proactive DDoS defenses.
Limit floods of traffic into target websites. DDoS hackers find databases to be tempting targets because their transaction rate limits are low. (That is, the system allows few database queries per second). When the number of requests to the database exceeds the limit, the database overloads, and freezes. Limiting the damage from DDoS attacks requires control of login attempts at the network edge. So, to keep the site open, security pros must increase the allowable rate of login requests.
Shift traffic to multiple servers during attacks. CDN structure is based on distributing multiple copies of content to different locations worldwide. When the tsunami of junk data floods a target server, CDN functions reduce the pressure on the target by rerouting attack data to different locations. In itself, load balancing measures are unlikely to mitigate an attack on its own. It is, however, likely to give the security team time to respond to the attack.
Block, clean, and divert infected content during attacks. Recent reports indicate that many DDoS exploits now deliver a one-two punch of disruption—DDoS attacks followed by application-layer attacks. The development of DDoS application attacks means that mitigation must address infections at a web site’s network and application levels. So, mitigation now involves:
- Scrubbing content generated by the attack. Cleaning up infected content occurs at scrubbing centers, where traffic is diverted, searched, and cleaned of malicious software.
- Block malicious traffic before it reaches the target web site. Some anti-DDoS methods use advanced data analytics to recognize and block malware, bots, and other malicious software from a target server.
- Protect against application-layer attacks. Anti-DDoS systems monitor site visitor behavior, block malicious software, and challenge unrecognized visitors with CAPTHA and cookie challenges.
These robust CDN capabilities make it easy to complete a shopping list of must-have, anti-DDoS features.
What to Look for in a CDN?
Given the hefty costs of a DDoS attack, it’s good to recognize the potential benefits of blocking or reducing DDoS-related losses. When you plan to install or design anti-DDoS infrastructure, consider these capabilities:
- Threat intelligence data analytics. TI enables a faster response to DDoS-related attacks. And they enable the security team to reduce or eliminate attack-related downtime.
- Load balancer. Load balancing decreases the risk of site failure by reducing the attack surface and eliminating single points of failure during DDoS attacks.
- Rate limiting. CDN servers monitor, measure, and analyze inbound traffic. When traffic builds up during a DDoS attack, CDNs reduce the risk of site failure caused by database query rates that are too low.
- Data scrubbing. You can block, clean, and reroute malicious content before it can infect your site, often without users being aware that anything happened.
- Automated failover. CDNs also reduce or eliminate downtime caused by DDoS attacks. If a local server is targeted by hackers, the CDN server can stop inbound traffic to the target and failover to a backup.
So, the next time DDoS attack statistics make you nervous, remember that fully equipped CDN environments can reduce the risk and costs of modern DDoS exploits.
